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== Guides == | |||
{{List Guides}} | |||
== Device pictures == | |||
==Device pictures== | |||
<gallery showthumbnails="1"> | <gallery showthumbnails="1"> | ||
File:Example device pictures.jpg | File:Example device pictures.jpg | ||
</gallery> | </gallery> | ||
==PCB pictures== | == PCB pictures == | ||
<gallery showthumbnails="1"> | <gallery showthumbnails="1"> | ||
File:Example pcb pictures.jpg | File:Example pcb pictures.jpg | ||
</gallery> | </gallery> | ||
==Reference measurements (also schematics if available)== | == Reference measurements (also schematics if available) == | ||
<gallery showthumbnails="1"> | <gallery showthumbnails="1"> | ||
File:Example measurement pictures.jpg | File:Example measurement pictures.jpg | ||
</gallery> | </gallery> | ||
==External Sources== | == More Information/External Sources == | ||
=== Potential pitfalls === | |||
== Potential pitfalls == | * The motherboard will not turn on without the I/O SubCard connected. Actually it will turn on and then immediately assert -PWRSHUTDOWN, which will cause the first mosfet (Q9) to immediately go off. This is most likely because the subcard has a power switch or regulator on it that is turned on by the VCC5MUBAY_DRV signal, and then the EC expects VCC5MUBAY to go high, and when it doesn't see it go high, it assumes something is wrong and turns off. Temporarily shorting TP28(VCC5M_IO_PWR-) to TP29(VCC5MUBAY) allows the motherboard to turn on even without the I/O SubCard. | ||
The motherboard will not turn on without the I/O SubCard connected. Actually it will turn on and then immediately assert -PWRSHUTDOWN, which will cause the first mosfet (Q9) to go off. This is most likely because the subcard has a power switch or regulator on it that is turned on by the VCC5MUBAY_DRV signal, and then the EC expects VCC5MUBAY to go high, and when it doesn't see it go high, it assumes something is wrong and turns off. Temporarily shorting TP28(VCC5M_IO_PWR-) to TP29(VCC5MUBAY) allows the motherboard to turn on even without the I/O SubCard. When flashing the BIOS using a SOIC clip, the programmer device needs to strongly drive the HOLD# pin high. A 5.6kOhm pull-up was not strong enough. A dead short worked successfully. The 4MiB and 8MiB BIOS flash chips share MISO/MOSI/SCK lines. When programming them using a SOIC clip, it has been observed that often the CS# line of the other chip has a low enough voltage and that the other chip could be considered selected as well. This did not cause a reading/programming failure so far, but if any issues are observed in the future, then it may be worth forcing the CS# line of the other chip high. | * When flashing the BIOS using a SOIC clip, the programmer device needs to strongly drive the HOLD# pin high. A 5.6kOhm pull-up was not strong enough. A dead short worked successfully. | ||
* The 4MiB and 8MiB BIOS flash chips share MISO/MOSI/SCK lines. When programming them using a SOIC clip, it has been observed that often the CS# line of the other chip has a low enough voltage and that the other chip could be considered selected as well. This did not cause a reading/programming failure so far, but if any issues are observed in the future, then it may be worth forcing the CS# line of the other chip high. | |||
Latest revision as of 20:14, 14 January 2024
| Thinkpad W541 | |
|---|---|
| Manufacturer | Lenovo |
| Code name | W541 |
| Release date | |
| Device type | Laptop |
This article is a stub. You can help Repair Wiki grow by expanding it
Guides
Explanatory Guides
Repair Guides
Create a Guide
Device pictures
Please consider contributing pictures to this section!
PCB pictures
Please consider contributing pictures to this section!
Reference measurements (also schematics if available)
Please consider contributing pictures to this section!
More Information/External Sources
Potential pitfalls
- The motherboard will not turn on without the I/O SubCard connected. Actually it will turn on and then immediately assert -PWRSHUTDOWN, which will cause the first mosfet (Q9) to immediately go off. This is most likely because the subcard has a power switch or regulator on it that is turned on by the VCC5MUBAY_DRV signal, and then the EC expects VCC5MUBAY to go high, and when it doesn't see it go high, it assumes something is wrong and turns off. Temporarily shorting TP28(VCC5M_IO_PWR-) to TP29(VCC5MUBAY) allows the motherboard to turn on even without the I/O SubCard.
- When flashing the BIOS using a SOIC clip, the programmer device needs to strongly drive the HOLD# pin high. A 5.6kOhm pull-up was not strong enough. A dead short worked successfully.
- The 4MiB and 8MiB BIOS flash chips share MISO/MOSI/SCK lines. When programming them using a SOIC clip, it has been observed that often the CS# line of the other chip has a low enough voltage and that the other chip could be considered selected as well. This did not cause a reading/programming failure so far, but if any issues are observed in the future, then it may be worth forcing the CS# line of the other chip high.